This invention relates to metallized labels generally, and more specifically, but without limitation, to die cut or patch metallized labels for use with cold glue, and to films for making such labels. In one aspect, the invention relates to the use of such labels on substrates, where the label forms a destruct bond with the substrate such that the label delaminates. In another aspect, the invention relates to labels which possess the beneficial properties of the known thermoplastic labels, but which exhibit improved initial adhesion and destruct bonding, such as delamination.
In many label applications, it is desirable that the label stock from which the labels are cut be a film of polymeric material rather than paper. Polymeric film can provide one or more of the following properties lacking in paper: durability, strength, water resistance, curl resistance, abrasion resistance, gloss, transparency and other properties. Obviously, the polymeric material must meet the practical requirements of commercial manufacture and use. Material costs must be competitive. The film must be formable by a suitable commercial process, such as cast film extrusion or blown film extrusion, requiring that the molten film material be flowable to the correct degree to accomplish proper film formation. The formed film must be capable of hot-stretching without deleterious effect, because it is generally advantageous to hot-stretch and anneal the formed film, so as to orient the film and impart a stiffness to the film that is different in machine and cross directions. The film must have a printable face and be die-cuttable and matrix-strippable when used in a pressure-sensitive label construction.
In the die cut, cold glue label applications, there are certain other desired characteristics. Cold glues are widely used as an economical alternative to wrap-around or pressure-sensitive labels. Cold glue labels must be capable of providing a means for drying the adhesive and providing good initial adhesion, while not exhibiting visual defects.
Olefin blends have been found in many respects to be a preferred material to meet the demands of polymeric, die-cut label manufacture. The relatively low cost of the olefinic resins, and their high strength allowing for low caliper film, tend to minimize overall material cost. Hot-stretched polypropylene and/or polyethylene provides stiffness in the machine direction even at relatively low-caliper thicknesses for adequate print registration and dispensing while providing sufficiently low tensile modulus and, in particular, sufficiently high elongation in the cross direction to allow good conformability.
Olefin blends have been found useful to produce, on an economical basis, printable 3.5 mil (caliper measured) coextruded labels die-cut from biaxially hot-stretched film that are durable, strong and water-resistant, and that generally have good structural and surface properties and performance characteristics. Biaxial stretching also makes an important contribution to performance by creating substantial differentials between machine direction (MD) and cross direction (CD) stiffnesses, tensile moduli, elongations, and other properties.
Paper labels have been used in the art in conjunction with a cold glue adhesive for application to glass and plastic containers. The paper labels exhibit good initial adhesion, adhesive drying, and destruct bonds. A metallized layer may be applied to paper labels to achieve a metallized graphic appearance. However, the inherent surface roughness of some papers does not encourage a highly reflective mirror-like surface.
U.S. Pat. No. 4,060,168 discloses a label assembly that includes a strip or web of backing material with a series of printed labels arranged in serial order. The backing material includes a die cut portion opposed to the label, which remains adhered to the label upon application of the label to a container. The cut portion may include printing and serves as a promotional item with improved pilfer resistance. U.S. Pat. No. 4,060,168 is incorporated herein by reference.
U.S. Pat. No. 5,061,334 discloses a high speed labeling machine and method for transferring labels to articles, such as cans. The labeling machine includes a device for supplying articles to be labeled, a label transfer wheel provided with individual groups of closely-spaced vacuum holddown ports to enable a succession of closely-spaced labels to be supported by the transfer wheel and carried by the transfer wheel to the articles, and a pressure-severing device for releasing the label from a carrier stock for subsequent transfer from a transfer wheel to the article to be labeled. Sprocket holes are utilized to precisely align a label. The labels may be die cut on the printing press and retained on the carrier by pinpoint attachments or they may be die cut as the label is advanced. In one particular embodiment, single layer label tapes with release agent on one surface and a pressure sensitive adhesive on the other surface provide added advantages of smaller spool sizes and faster speeds. Single layer label tapes also make tamper-evident packaging very versatile and advantageous. Another aspect disclosed in this patent is the significantly improved economics by reducing the number of layers to one instead of two for normal pressure sensitive labels as well as by eliminating the cost and problems associated with using glue applicators with many types of labeling products. U.S. Pat. No. 5,061,334 is incorporated herein by reference.
U.S. Pat. No. 5,174,852 discloses a method for attaching labels to containers where the labels are removed from a stack by rolling contact with an adhesive surface coated with a cold glue. Additionally, prior to termination of the removing step, localized hot glue coating is applied to the foremost label in the stack. After the label has thus been coated with cold glue and hot glue, it is peeled off the adhesive surface and pressed into contact of its glue-coated backside with a container. The provision that the hot glue coating is applied to the label while it is still held in the magazine ensures that the shape and position of the hot glue coating is fully independent of the speed of the labeling operation. U.S. Pat. No. 5,174,852 is incorporated herein by reference.
U.S. Pat. No. 5,288,548 discloses a multilayer label stock structure comprising a label stock of polypropylene film having on one side thereof a highly printable blend of (A) alkaline acrylate copolymer and (B) an interpolymer of an alkyl acrylate, an alkyl methacrylate and an alkyl acrylate acid. U.S. Pat. No. 5,288,548 is incorporated herein by reference.
U.S. Pat. No. 5,486,253 discloses a method of labeling containers utilizing a labeler having a multiple port vacuum drum. The multiple port vacuum drum has a first cavity which is supplied with one level of vacuum suitable for picking up label segments from a cutter with limited tension. The vacuum drum has a second cavity, which is supplied with another, higher level of vacuum suitable for firmly griping the label segments as an adhesive or the like is applied to the label segment. The second cavity may be further divided into a label application segment with lower vacuum pressure. The cutter drum has an arcuate cavity to which vacuum is supplied at the end first contacting the labeling material web with reduced vacuum being provided at the label cut off point and label release point. U.S. Pat. No. 5,486,253 is incorporated herein by reference.
U.S. Pat. No. 5,897,722 discloses a process for applying labels to articles by first adhering a limited portion of the label to the article and subsequently making additional portions of the label adhesive so that they will adhere to the article after the label is affixed to the article. The leading and trailing edges of the label may be bonded to the article or each other to affix the label to a container or other such article. The portions of the label between the leading and trailing edges may be either provided with an adhesive agent that is in a non-adhesive state or be formed from a label material which is not normally adhesive but can be rendered adhesive through an additional process step. For example, coated polyethylene film can be applied to a container by means of a hot melt adhesive and then subsequently heated to a temperature at which the polyethylene material becomes adhesive causing it to stick to the container. Other labeling materials can be printed with an adhesive that remains substantially non-adhesive until heated or activated by means of radiation, application of a chemical activating agent or by application of mechanical force. U.S. Pat. No. 5,897,722 is incorporated herein by reference.
U.S. Pat. No. 6,083,342 discloses a system and method for rapidly labeling a blow-molded hollow container made of a plastic composition subject to out-gassing after de-molding. Otherwise, conventional high speed silk screen labeling technology and processing is employed shortly after container fabrication de-molding in order to accurately deposit a continuous liquid layer of conventional silk screen ink over an external container surface area designated for application thereon of a self-adhering pre-printed label. The label is rapidly and accurately transfer applied over the silk screen coated area immediately after the same has dried, and even while out-gassing is still occurring from the de-molded to container. However, the protective ink barrier coating prevents formation of bubbles beneath the label. Those gases in the container wall resident beneath the label-affixed area can then nevertheless out-gas by migrating out of the container internal wall surface. Also, labeling may be silk screen imprinted on the container surface in a designated label-receiving area, and/or on non-designated surface area concurrently with barrier coating of the designated area. A gas-blocking clear ink barrier layer may be silk screened over the silk screen imprinting, and then the label applied over the gas-blocking layer of clear ink when dry. The label may be “peelable” for customer rebate return without thereby altering the labeling information remaining on the container. The pre-printed label may be a replicate of the label-covered imprinting so that the “trade dress” need not be altered by the peelable label, and so that the container surface area available for permanent labeling is maximized. U.S. Pat. No. 6,083,342 is incorporated herein by reference.
U.S. Pat. No. 6,139,935 discloses an oxygen-absorbing label consisting of a base sheet, adhesive on the base sheet for securing the base sheet to an internal surface of a container, an oxygen-absorbing composition on the base sheet, and a cover sheet secured to the base sheet to confine the oxygen-absorbing composition there between. The cover sheet is fabricated of material which will permit oxygen to pass therethrough but will not stain due to the oxidation of the oxygen-absorbing composition or due to contact with materials in the container. A plurality of the foregoing labels are mounted on a web to be used with conventional labeling equipment. U.S. Pat. No. 6,139,935 is incorporated herein by reference.